/*
 *  NFCSigning - Open source library for signing/validation of NDEF messages
 *  Copyright (C) 2009-2010 The NFCSigning Team
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 */
package org.nfcsigning.algorithm;

import java.security.MessageDigest;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.digests.SHA1Digest;

/**
 *
 * @author Markus Kilås
 */
public class DigestFactory {

    public static Digest getDigest(String algorithm) {
        Digest d = null;
        
        if("SHA-1".equals(algorithm)) {
            if(ImplementationDetector.getInstance().isSatsaAvailable()) {
                MessageDigest md = null;
                try {
                    md = MessageDigest.getInstance("SHA-1");
                } catch(Exception ex) {}
                
                if(md != null) {
                    d = new SatsaSha1Digest(md);
                }
            }
            
            if(d == null) {
                d = new SHA1Digest();
            }
        }
        
        return d;
    }
    
}
